1. Field of the Invention
The present invention relates to hand tools, and more particularly to hand tools for removing a spring from a drum brake on a motor vehicle.
2. Discussion of the Related Art
Drum brakes are well known in the art and need not be described in detail. It is sufficient to say that in operation, drum members concentric with a wheel of a vehicle are forced outward by a piston which causes the members to engage a portion of the rotating wheel to effect stopping. When the brakes are not in use, a biasing spring pulls the drum members radially inwardly, away from the wheels, preventing frictional interference. A brake shoe hold down spring aids in preventing frictional interference.
During the course of brake maintenance, it becomes necessary to remove the brake shoe hold down spring from the brake shoe. Tension in the spring makes it difficult to remove; therefore, there exists a need to provide a tool to facilitate the removal of the brake shoe hold down springs from the brake assembly in a reliable and secure way. Furthermore, because of the specific application of such a tool, it should not have a high cost; thus the tool should be designed so that it may be manufactured with relative ease.
Tools relating to brake springs tend to focus on different methods of gripping the brake spring. Some tools provide ease of use and/or construction simplicity. Some brake spring tools use a simple V-shaped cut with which to push on the spring. This allows an unsecured hold on the spring that sometimes results in inadvertent release of the spring not without unwanted consequences. Such a slip can be dangerous to the repair person. Improved tools combine modified V-shaped cuts or other solutions for removing brake springs. However, none show the particular characteristics of the present invention.
For example, U.S. Pat. No. 4,625,353, issued Dec. 2, 1986, to Tamez et al., describes a tool for adjusting a brake mechanism of a truck-trailer having socket members at one end of a long cylindrical member. The socket members have a plethora of modified cylindrical openings which are adapted to fit adjustment screws of different head configurations. A removable socket member is provided with a swivel device for use on awkwardly-located adjustment screws and for use with interchangeable sockets. The Tamez device is not adapted to be used for tightening brake springs, lacking structure accommodating a brake spring, as well as the angle of attack required to facilitate tightening.
U.S. Pat. No. 4,813,120, issued Mar. 21, 1989, to Fournier, describes a method for removing O-rings and backup rings from annular indentations. The tool described includes an elongated rod with curved prying portions at each end. The tool does not include a flat end formation that ensnares the lead of a brake spring during disassembly of same from a brake shoe.
U.S. Pat. No. 4,870,737, issued Oct. 3, 1989, to Navarro, describes a device having laterally-extending spurs which engage the coiled portion of the spring, allowing the user to remove or install the spring. The Navarro device has an unnecessary multiplicity of parts and does not grip a brake spring in as secure a manner as the present device.
U.S. Pat. No. 4,876,022, issued Dec. 11, 1990, to Thornton et al., describes a tool having a lever with a rectangular cross-section. The tool has a power arm, a work arm, having a mechanism to engage an anchoring loop, eye, or hook at the end of a helical spring, and a fulcrum member adapted to rest on the spring. The Thorton tool does not allow easy access to a brake spring.
U.S. Pat. No. 5,095,603, issued Mar. 17, 1992, to Carruthers et al., describes a drum brake service tool, and method of using the same, including a lever with a pair of spaced, parallel arms disposed at a first end, wherein the arms are adapted to receive a brake spring substantially perpendicular therebetween. The Carruthers et al. device is not of an ergonomic design, does not lend itself to ease of manufacture, and does not provide simple access to a brake spring.
U.S. Pat. No. 5,165,154, issued Nov. 24, 1992, to Miller, describes an apparatus for attaching and removing a spring connecting a set of brake shoes including a rigid plate which is adapted to be slidingly positioned between facing ends of brake shoes. A separate, hand-held instrument has a slot adapted to receive a spring lead and a contoured tip adapted to dislodge the spring lead from the brake shoe seat. The Miller device is limited by two separate elements which cooperate to manipulate the spring into proper engagement with the brake shoes.
U.S. Pat. No. 5,191,690, issued Mar. 9, 1993, to Koehn, describes a brake tool including an open socket-like working end with semi-circular mounting flanges adapted to position and secure a spring clip. The tool is not adapted to trap the elongate lead of a brake spring.
U.S. Pat. No. 5,237,729, issued Aug. 24, 1993, to Martin, describes a brake spring application device including a crook-shaped working end having a protrusion positioned at the outer central portion of the crook and lateral slot configured to secure the tool to a pin during dislodgement of the spring from the brake shoe. The tool is not configured to positively seize and maintain a brake spring lead during its dislodgement.
U.S. Pat. No. 5,253,406, issued Oct. 19, 1993, to Shere el al., describes a brake clip tool. The tool is not adapted to manipulation of brake springs.
U.S. Pat. Nos. 5,345,664, issued Sep. 13, 1994, to McMahon et al., and 5,507,083, issued Apr. 16, 1996, to Redgrave et al., illustrate apparatuses for removing brake springs. Each apparatus includes an elongated lever having a bifurcated gripping member designed to fit over a lip of a lower brake shoe. Then the elongated lever may be rotated until the other end thereof may be placed around a brake spring shaft of a brake spring, thereby allowing the brake spring to be removed. The tool is configured such that a different length lever must be used for every brake size and there is the danger that the lever might slip before the spring is released.
U.S. Pat. No. 5,367,755, issued Nov. 29, 1994, to Wood, describes an expansion tool adapted to manipulate a spring. The tool is not adapted to seize and securely remove a brake spring lead from a brake shoe.
U.S. Pat. No. 5,392,504, issued Feb. 28, 1995, to Calusinski, describes a tool for removal of retaining spring clips on rail way tracks. The device is not intended to remove, thus does not accommodate automotive brake springs.
U.S. Pat. No. 5,455,996, issued Oct. 10, 1995, to Ploeger et al., illustrates a brake spring roll hand tool for removing springs from brake drums. The device includes a straight shaft with a threaded end. A collar, having a notch angled back toward the handle, has an axial threaded passage in communication with the notch such that the threaded shaft may be received therein to trap a spring lead in the notch. Because brake springs typically tend to be located in such a manner as to prevent a straight shafted tool from reaching the leads thereof, the Ploeger et al. tool may not be useful in many applications. Also the tool requires two, machined, interconnecting parts. Further, the threaded clamping system requires considerable time positioning the tool and securing the spring lead therein, which slows the repair process.
In light of the above, despite the attempts made by the prior art devices, there still exists a need for an improved brake spring tool which allows quick yet functional access to brake spring lead. None of the prior art patents, taken alone or in combination, teaches or suggests the presently claimed brake spring tool.